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BUN /Creatinine Ratio : 296
Test CodeBCRAU or 296
Alias/See Also
Blood Urea Nitrogen; BUN
CPT Codes
82565, 84520
Preferred Specimen
2 mL serum
Minimum Volume
1 mL
Other Acceptable Specimens
Spun SST tube
Transport Container
Serum separator tube (SST)
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 7 days
Refrigerated: 5 days
Frozen: 28 days
Refrigerated: 5 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Plasma
Methodology
See individual tests
Setup Schedule
Sunday - Saturday
Report Available
1 day
Reference Range
Urea Nitrogen (BUN)
Age Male (mg/dL) Female (mg/dL)
<1 Month 4-12 3-17
1-11 Months 2-13 4-14
1-3 Years 3-12 3-14
4-19 Years 7-20 7-20
≥20 Years 7-25 7-25
Creatinine
Age Male (mg/dL) Female (mg/dL)
≤2 days 0.79-1.58 0.79-1.58
3-27 days 0.35-1.23 0.35-1.23
1 month-9 years 0.20-0.73 0.20-0.73
10-12 years 0.30-0.78 0.30-0.78
13-15 years 0.40-1.05 0.40-1.00
16-17 years 0.60-1.20 0.50-1.00
18-29 years 0.60-1.24 0.50-0.96
30-39 years 0.60-1.26 0.50-0.97
40-49 years 0.60-1.29 0.50-0.99
50-59 years 0.70-1.30 0.50-1.03
60-69 years 0.70-1.35 0.50-1.05
70-79 years 0.70-1.28 0.60-1.00
≥80 years 0.70-1.22 0.60-0.95
For patients >49 years of age, the upper reference limit for creatinine is approximately 13% higher for people identified as African-American.
eGFR ≥60 mL/min/1.73m2
Bun/Creatinine Ratio
<1 year Not Established
1-5 years 16-50 calc
6-10 years 13-36 calc
11-16 years 9-25 calc
≥17 years 6-22 calc
Age Male (mg/dL) Female (mg/dL)
<1 Month 4-12 3-17
1-11 Months 2-13 4-14
1-3 Years 3-12 3-14
4-19 Years 7-20 7-20
≥20 Years 7-25 7-25
Creatinine
Age Male (mg/dL) Female (mg/dL)
≤2 days 0.79-1.58 0.79-1.58
3-27 days 0.35-1.23 0.35-1.23
1 month-9 years 0.20-0.73 0.20-0.73
10-12 years 0.30-0.78 0.30-0.78
13-15 years 0.40-1.05 0.40-1.00
16-17 years 0.60-1.20 0.50-1.00
18-29 years 0.60-1.24 0.50-0.96
30-39 years 0.60-1.26 0.50-0.97
40-49 years 0.60-1.29 0.50-0.99
50-59 years 0.70-1.30 0.50-1.03
60-69 years 0.70-1.35 0.50-1.05
70-79 years 0.70-1.28 0.60-1.00
≥80 years 0.70-1.22 0.60-0.95
For patients >49 years of age, the upper reference limit for creatinine is approximately 13% higher for people identified as African-American.
eGFR ≥60 mL/min/1.73m2
Bun/Creatinine Ratio
<1 year Not Established
1-5 years 16-50 calc
6-10 years 13-36 calc
11-16 years 9-25 calc
≥17 years 6-22 calc
Clinical Significance
The BUN/Creatinine ratio is useful in the differential diagnosis of acute or chronic renal disease. Reduced renal perfusion, e.g., congestive heart failure, or recent onset of urinary tract obstruction will result in an increase in BUN/Creatinine ratio. Increased urea formation also results in an increase in the ratio, e.g., gastrointestinal bleeding, trauma, etc. When there is decreased formation of urea as seen in liver disease, there is a decrease in the BUN/Creatinine ratio. In most cases of chronic renal disease the ratio remains relatively normal.
Performing Laboratory
med fusion